1. Field of the Invention
The present invention relates to an active electronic tag apparatus for a memory card and includes a structure and related modulation method of the active electronic tag apparatus.
2. Description of the Prior Art
With the development of wireless technology, an electronic tag, which includes a radio frequency circuit and is utilized for storing information, has been widely used, such as identification, an access control system or electronic money. A typical electronic tag is passive, which receives a detecting signal and a carrier transmitted from a card reader as a power source, and utilizes a coupling effect between antennas to change a voltage of the card reader by a load variation of the electronic tag, so as to transmit information.
Electronic products are required to be slim and light; however, the dimension of the electronic tag is difficult to be decreased due to the limitation of the antenna area of the electronic tag. The reason is that the antenna area of the electronic tag relates to the transmitting distance. When the antenna area of the electronic tag is reduced, the coupling coefficient between the antenna of the electronic tag and the antenna of the card reader is decreased. As a result, the load variation of the electronic tag is difficult to change the voltage of the card reader, and information of the electronic tag cannot be effectively transmitted to the card reader.
Thus, in order to effectively transmit information while minimizing the electronic tag, to meet various applications, there is an urgent need for improvement over the prior art.